Robotic diagnostic and interventional systems and devices are well suited for use in performing minimally invasive medical procedures, as opposed to conventional techniques wherein a patient's body cavity is open to permit the surgeon's hands access to the internal organs. There is a need for highly controllable yet minimally sized systems to facilitate imaging, diagnosis, and treatment of tissues which may lie deeply and/or concealed within the body cavity of a patient, and which may be accessed through natural body orifices or percutaneous incisions and by way of naturally-occurring pathways such as blood vessels or other bodily lumens.